/*
 * Copyright 2002-2013 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.xiongyingqi.util.xml;

import org.xml.sax.ContentHandler;

import javax.xml.stream.XMLEventFactory;
import javax.xml.stream.XMLEventWriter;
import javax.xml.stream.XMLStreamWriter;
import javax.xml.transform.sax.SAXResult;

/**
 * Implementation of the {@code Result} tagging interface for StAX writers. Can be constructed with
 * an {@code XMLEventConsumer} or an {@code XMLStreamWriter}.
 * <p/>
 * <p>This class is necessary because there is no implementation of {@code Source} for StaxReaders
 * in JAXP 1.3. There is a {@code StAXResult} in JAXP 1.4 (JDK 1.6), but this class is kept around
 * for backwards compatibility reasons.
 * <p/>
 * <p>Even though {@code StaxResult} extends from {@code SAXResult}, calling the methods of
 * {@code SAXResult} is <strong>not supported</strong>. In general, the only supported operation
 * on this class is to use the {@code ContentHandler} obtained via {@link #getHandler()} to parse an
 * input source using an {@code XMLReader}. Calling {@link #setHandler(org.xml.sax.ContentHandler)}
 * will result in {@code UnsupportedOperationException}s.
 *
 * @author Arjen Poutsma
 * @see javax.xml.stream.XMLEventWriter
 * @see javax.xml.stream.XMLStreamWriter
 * @see javax.xml.transform.Transformer
 * @since 3.0
 */
class StaxResult extends SAXResult {

    private XMLEventWriter eventWriter;

    private XMLStreamWriter streamWriter;


    /**
     * Construct a new instance of the {@code StaxResult} with the specified {@code XMLStreamWriter}.
     *
     * @param streamWriter the {@code XMLStreamWriter} to write to
     */
    StaxResult(XMLStreamWriter streamWriter) {
        super.setHandler(new StaxStreamContentHandler(streamWriter));
        this.streamWriter = streamWriter;
    }

    /**
     * Construct a new instance of the {@code StaxResult} with the specified {@code XMLEventWriter}.
     *
     * @param eventWriter the {@code XMLEventWriter} to write to
     */
    StaxResult(XMLEventWriter eventWriter) {
        super.setHandler(new StaxEventContentHandler(eventWriter));
        this.eventWriter = eventWriter;
    }

    /**
     * Construct a new instance of the {@code StaxResult} with the specified {@code XMLEventWriter}
     * and {@code XMLEventFactory}.
     *
     * @param eventWriter  the {@code XMLEventWriter} to write to
     * @param eventFactory the {@code XMLEventFactory} to use for creating events
     */
    StaxResult(XMLEventWriter eventWriter, XMLEventFactory eventFactory) {
        super.setHandler(new StaxEventContentHandler(eventWriter, eventFactory));
        this.eventWriter = eventWriter;
    }


    /**
     * Return the {@code XMLEventWriter} used by this {@code StaxResult}. If this {@code StaxResult}
     * was created with an {@code XMLStreamWriter}, the result will be {@code null}.
     *
     * @return the StAX event writer used by this result
     * @see #StaxResult(javax.xml.stream.XMLEventWriter)
     */
    XMLEventWriter getXMLEventWriter() {
        return this.eventWriter;
    }

    /**
     * Return the {@code XMLStreamWriter} used by this {@code StaxResult}. If this {@code StaxResult}
     * was created with an {@code XMLEventConsumer}, the result will be {@code null}.
     *
     * @return the StAX stream writer used by this result
     * @see #StaxResult(javax.xml.stream.XMLStreamWriter)
     */
    XMLStreamWriter getXMLStreamWriter() {
        return this.streamWriter;
    }


    /**
     * Throws an {@code UnsupportedOperationException}.
     *
     * @throws UnsupportedOperationException always
     */
    @Override
    public void setHandler(ContentHandler handler) {
        throw new UnsupportedOperationException("setHandler is not supported");
    }

}
